Chandler1, as chemicals, the alum and lime pose no danger to your fish. Your high PH would allow you to add only the alum, which should always be applied first anyway. The hydrated lime can raise the PH to lethal levels rapidly and is why it should never be applied first.
Alum will lower your PH, but it occurs slowly. With your PH at 9, you might benefit from not adding the hydrated lime at all. Keep some test strips handy, test your PH BEFORE applying all 200 pounds of Alum and then check your PH every 15 minutes or so after all the alum is applied for a couple hours. If your PH only drops by .1 or .3 every 15 minutes, your fish will be just fine with no danger of PH shock. If the PH drops by more than .5 in 15 minutes, broadcast spread the lime to counteract the alum, but I don't see you needing to do this.
